What is Down syndrome?

Down syndrome is a genetic (chromosomal) condition that is present from conception. It happens when a baby has extra chromosome 21 material and may sometimes be called Trisomy 21. 

Down syndrome happens in families of all backgrounds. It is not caused by anything you or your partner did before or during pregnancy.

Down syndrome can be associated with a range of physical features and differences in development and learning, including some level of intellectual disability (this varies from person to person).

Some people with Down syndrome have additional health conditions (for example, heart, hearing, vision or thyroid conditions). Not everyone will have the same health concerns, and many can be treated or well managed with the right care.

Screening or diagnostic tests can tell you whether Down syndrome is likely or confirmed, but they cannot predict a child’s individual strengths, support needs or day to day life

It is a congenital condition (a baby is born with it). 

People living with Down syndrome may have differences in learning and development, including some level of intellectual disability. This can vary from person to person. Some people may take longer to learn new skills and may have differences in speech and language development.

Some people with Down syndrome also have physical characteristics. These can vary a lot, and not everyone will have the same features.

Physical characteristics may include:

• short height, and differences in head or facial shape
• eyes that slant upwards
• differences in the shape of the outer ear
• a flat facial profile (side view of the face)
• low muscle tone (floppy muscles)
• extra skin at the back of the neck
• a single crease (line) across the palm

People living with Down syndrome are all different. They may share some characteristics but they do not all look the same, have the same abilities or health needs.

Down syndrome is when a baby is born with an extra copy of chromosome 21. Chromosomes are small, organised bundles of genetic information inside your cells, with instructions that help your body grow. 

Most people have 46 chromosomes, arranged in 23 pairs. People living with Down syndrome have 47 chromosomes because they have 3 copies of chromosome 21 instead of 2. This extra copy changes how the body and brain develop.

The extra chromosome usually appears because of a random change when cells are dividing at conception (when the egg is fertilised by the sperm). It is important to understand that Down syndrome:

• is not anyone’s fault
• doesn’t happen because of anything you or your parents did
• is usually not inherited (passed from one generation to another)

The chance of having a child living with Down syndrome increases with the age of the mother but anyone can have a baby with Down syndrome at any age.

Screening tests check your baby’s chance of being born with a genetic (chromosomal) difference such as Down syndrome. It is your choice whether to have these tests. 

Screening is offered to everyone during pregnancy, usually during the first trimester. It is different from routine antenatal tests. 

Screening may include an ultrasound scan and blood tests. These tests are safe and do not harm you or your baby. There are 3 ways to screen for Down syndrome:

• combined first trimester screening
• non-invasive prenatal testing (NIPT)
• second trimester serum screening

A screening test cannot diagnose Down syndrome. A ‘high risk result’ means it is more likely that there is a difference present.

Tests during pregnancy that can confirm whether your baby has Down syndrome include:

• chorionic villus sampling — which tests the placental tissue
• amniocentesis — which tests the amniotic fluid (the fluid around your baby)

After your baby is born, a blood test may be done to confirm Down syndrome.

Finding out your baby has Down syndrome

Finding out that your baby may have, or has, Down syndrome can bring up many different feelings. There is no “right” way to feel.  It is important to talk with your doctor and midwife about what the test results mean.

They can:

• explain what your result shows (for example, the difference between a screening result and a diagnosis)
• talk through your options and support you to make a decision that feels right for you
• help you plan your pregnancy, birth and care (including any extra checks or appointments that may be recommended)
• offer or arrange genetic counselling so you can ask questions and get clear information
• connect you with support services and peer support, including families and lived experience resources, if you would like this

Read more about finding out your baby has Down syndrome.

Down syndrome is a lifelong genetic difference, not a condition that can be cured.

Support, regular health checks and early help with learning and development can support people with Down syndrome to live healthy lives. Support is based on each person’s needs, strengths and goals.

Babies and children living with Down syndrome will often have regular health checks so any health concerns can be found and treated early.

Some children may benefit from support such as:

• speech therapy
• physical therapy 
• occupational therapy

Extra support at school, home and in the community can help people living with Down syndrome reach their goals and enjoy a good quality of life. 

Raising a child living with Down syndrome can bring both joy and challenges. You may need support to manage your child’s health, learning and daily care. 

Support is available through health professionals, community services and Down syndrome associations. Ask your doctor, social worker or maternal child health nurse about local services and support groups. Many families also find it helpful to connect with other parents and lived experience supports, alongside clinical advice.

Read more about what support is available for families.

People living with Down syndrome may have a higher chance of some health conditions. 

These include physical and developmental conditions:

• heart conditions — may be present at birth
• hearing and vision differences — may affect learning if not corrected
• low muscle tone — may affect movement and strength
• sleep apnoea — when breathing stops and starts during sleep
• Alzheimer’s disease — memory loss and thinking difficulties later in life
• epilepsy — a condition that causes seizures

Some health conditions affect or are linked to the immune system:

• autoimmune conditions — such as thyroid problems, coeliac disease and type 1 diabetes
• weakened immune system — making it easier to get infections
• leukaemia — a type of blood cancer

Not everyone with Down syndrome will have these complications. Regular health checks can help find and treat health conditions early.

Down syndrome cannot be prevented.

Prenatal screening and diagnostic tests can check whether your baby may have, or has Down syndrome during pregnancy. They cannot stop it from happening.

Having these tests is your choice. Some people choose screening to help them prepare, plan care or reduce uncertainty. Others choose not to have screening, or not to have more testing after a result.

• Down Syndrome Australia has information, support and resources for people living with Down syndrome and their families. Call their national phone number on 1300 881 935 and ask for your local organisation.
• Through the Unexpected has information and support for parents who receive unexpected news about their baby during pregnancy.
• Prenatal Screening provides evidence‑based information to support informed choices about screening, diagnostic testing and pregnancy options. It also includes personal stories and support resources
• The Royal Australian and New Zealand College of Obstetricians and Gynaecologists provides more information on prenatal screening for chromosomal and genetic conditions.
• Children and Young People with Disability Australia (CYDA) provides information and support for children, young people living with disability and their families.
• Financial support is available through the National Disability Insurance Scheme (NDIS).
• The Human Genetics Society of Australasia has a find a genetic counsellor service.
• All Means All offers resources to help parents support their child's inclusive education.
• Key Word Sign Australia provides training and resources to support communication.
• Carer Gateway offers practical, emotional and financial support for carers.

Languages other than English

Down Syndrome Australia offers fact sheets and resources in languages other than English, as well as easy English versions. Topics include:

• advice for new parents with a baby living with Down syndrome
• a guide for expectant parents
• living independently
• an early years guide
• a video for parents of children living with Down syndrome talking about the diagnosis during pregnancy
• a video of parents of children living with Down syndrome talking about early intervention after their child's diagnosis

Parent Line is a free telephone counselling and support service for parents and carers. It offers parenting support for parents from culturally and linguistically diverse backgrounds.